This research program is concerned with the structure of the vitreous proteins which are responsible for the gel state of the tissue. Chemical studies are in progress to determine the composition of the helical and terminal peptides in vitreous collagen to define more closely the specific type of collagen and factors which may be responsible for the unique morphology of vitreous fibers. In addition varying quantities of other proteins and glycoproteins are associated with the vitreous fibers in the insoluble protein faction and these constituents are also present along with hyaluronic acid in the soluble fraction. Experiments are being carried out to isolate and characterize these vitreous constiuents. Comparative studies are being performed with the vitreous of bovine, ovine, lapine canine and human post-mortem eyes to determine both the species variation in chemical composition and structure and also the age related changes that occur. Tissue culture experiments with cells isolated from the fetal and young bovine retina are in progress to determine if these cells synthesize vitreous macromolecules.